This application claims the benefit of priority to Japanese Patent Application No. 2003-073215, herein incorporated by reference.
1. Field of the Invention
The present invention relates to a holder-mounted optical element in which a holder and an optical element are formed as a single piece, and more particularly, to a holder-mounted optical element formed by press-forming an optical element material within the holder.
2. Description of the Related Art
Optical elements, such as a lens mounted in the pickup head of a CD player and a lens used in a digital camera, require high precision when they are mounted. For example, as disclosed in patent document 1, in order to satisfy this requirement, a holder-mounted optical element in which a holder holds an optical element is generally manufactured, and its mounting position is adjusted by the holder, thereby improving mounting accuracy. The holder-mounted optical element is formed in such a manner that an optical element material, which is arranged inside a cylindrical holder, is softened by heating, the softened optical element material is press-formed by a metal mold to form an optical element, and at the same time, the optical element is compressed to the holder. In this way, the optical element and the holder are formed as a single piece.
[Patent Document 1]
Japanese Unexamined Patent Application Publication No. 3-265529 (FIG. 1)
However, in a case where an optical element material is press-formed, if there is any error in the volumetric metering of the optical element material, the thickness of the optical element material is changed. As a result, optical performance deteriorates, and an ideal optical location should be obtained for adjustment and fixation, causing problems in terms of performance and location determination.
To solve such problems, the volumetric metering of the optical element material should be precisely preformed to reduce the volume error. However, in order to make sure to obtain the desired effects, it is necessary to handle not only the volume of the optical element material but also the holder shape with high precision. However, in this case, material and processing costs increase.
The present invention is designed to solve such problems, and it is an object of the present invention to provide a high-precision holder mounted optical element that makes it possible to correct for errors in the volumetric metering of the optical element material.
To achieve this object, a holder-mounted optical element is provided, in which an optical element is accommodated into a cylindrical holder, wherein the holder has a thin deformation portion that is deformed by pressure applied from an inner circumferential side thereof, and a surplus portion, which press-contacts with the deformation portion, is formed in the optical element.
Also, according to the present invention, the surplus portion of the optical element is composed of a surplus of an optical element material, and the deformation portion is deformed by the pressure applied from the surplus portion.
Furthermore, according to the present invention, the thin deformation portion is formed in a part of the side surface of the holder, and the surplus portion is formed to outwardly protrude from a circumferential portion of the optical element.
Moreover, according to the present invention, the holder has a thin collar portion on the inner circumferential side, the collar portion serving as the deformation portion, and the surplus portion is formed around a tip portion of the inside of the collar portion.